Due to their fermentation processes in manufacturing, moist snuffs, particularly those without bacteriostatic flavors like methyl salicylate, have limited shelf-lives. After processing, moist snuffs generally contain 10.sup.5 to 10.sup.8 organisms per gram. These residual organisms destroy the flavor and reduce product acceptability by generating off flavors.
Various processes are known for treating tobacco for preparation for use in smoking articles or for smokeless tobacco products such as moist snuff.
A number of references teach the treating of tobacco with heat and/or steam to obtain specific characteristics in a tobacco product. For example, U.S. Pat. No. 3,262,458 teaches a method for conditioning and adjusting the moisture content of bulk leaf tobacco under vacuum and steaming conditions, and U.S. Pat. No. 4,315,515 teaches an apparatus for drying tobacco under relatively high absolute humidity drying conditions to increase the filling power of tobacco.
Fermentation processes for tobacco are also known. For example, U.S. Pat. No. 4,343,318 teaches an endothermic fermentation method of processing the tobacco, and aging the tobacco in an atmosphere containing more than 25 percent volume oxygen and preferably in either pure oxygen or oxygen-enriched air.
There are also a number of references that teach processes for the curing of tobacco. Such an example is U.S. Pat. No. 1,327,692 which teaches a controlled process of curing tobacco which is claimed to shorten the curing time over air curing processes, wherein the tobacco is subjected to various temperatures and humidity levels for various time intervals.
There are also a number of references which teach the processing of tobacco utilizable for snuff products. For example, U.S. Pat. No. 4,528,993 teaches a method to produce snuff comprising the steps of hogs-heads aging tobacco for about two years, blending the tobacco to produce a snuff mixture, cutting the blended mixture into particles, casing the cut mixture by applying casing materials to the mixture, forced-aging the mixture by inducing chemical reactions, top-dressing the mixture, and adjusting the moisture level of the mixture to a range of about 45-55 percent and packaging the adjusted mixture. U.S. Pat. No. 4,660,577 teaches a dry pre-mix, combined with water to obtain moist snuff wherein the pre-mix consists of a mixture of snuff-type tobacco cut to a predetermined size with a moisture level of between 6 percent and 16 percent.
U.S. Pat. No. 4,848,373 teaches a process for preparing moist snuff wherein tobacco having a moisture content of 25 percent to 53 percent, is adjusted to a ph of 8 to 11 with an alkalizing agent and the tobacco is maintained in an aerobic environment at a temperature of 40.degree. F. to 120.degree. F., and at a pressure of one atmosphere for a period of 4 to 14 weeks.
There are also a number of references which teach sterilization processes for vegetable products, including tobacco. For example, U.S. Pat. No. 3,721,527 teaches a method of sterilizing bulk batches of material by means of steam or hot gas, and centrifugation of the batches of material in a closed chamber with simultaneous addition of sterilizing medium. U.S. Pat. No. 4,234,537 teaches a batch process for the sterilization of particulate solid material in which a batch of particulate solid material to be sterilized is introduced into a rotary vessel shaped so that rotation of the vessel imparts a tumbling action to the solid material, wherein the material is heated in the vessel during rotation and a liquid lubricant is subjected under pressure into the vessel at a temperature in excess of the temperature of the solid, and the lubricant liquid and the solid material are tumbled at a sterilization temperature. U.S. Pat. No. 4,844,933 teaches a method for sterilizing raw vegetable products such as herbs and spices. However, none of the heretofore mentioned references incorporate the sterilization process of the present invention before the addition of flavorants to manufacture a snuff product having enhanced flavor characteristics and a long shelf life.
Early attempts to develop moist snuff products have relied on pressure cooking and chemical additives to develop the desired color, texture, and pH of the product. Products which incorporate chemical preservatives or no preservatives suffer in product quality because the residual microorganisms literally eat the flavor compounds and degrade the tobacco product. All of the commercially known methods of stabilizing snuff products are directed toward sterilization of the products after the addition of the flavoring ingredients; however, the flavoring ingredients are subjected to heat degradation. The instant invention utilizes a stabilization process developed to prevent the loss of flavor and prevent the continued fermentation which greatly limits product shelf life.
In the present invention, a moist snuff product is prepared using traditional blending and fermentation processes such as are described in U.S. Pat. No. 4,660,577 and U.S. Pat. No. 4,528,993.
As disclosed in U.S. Pat. No. 4,528,993, snuff is composed primarily of tobaccos varieties such as Dark Fired, Green River, and One-Sucker tobaccos, primarily from Tennessee and Kentucky. Physically, these tobaccos are heavy-bodied, having long, wide leaves. The manufacture of tobacco snuff products requires that the tobacco have the desired flavor characteristics, and the ability to withstand snuff manufacturing processing. A traditional tobacco snuff blend may contain a mixture of leaves and stems.
Traditional snuff processing begins with tobacco which has been packed in hogsheads for aging. The tobacco is packed having a moisture content in the 15 to 25% range, and stored for a period of three to five years to aid in the fermentation of the snuff-type tobaccos. After the aged tobacco is removed from the hogshead, sufficient water is added to bring moisture content of the tobacco to the 20 to 25% range. The moist tobacco is then subjected to a fermentation process whereby bacteria produce enzymes which reduce the natural sugars present in the tobacco to produce the flavor precursors unique to moist snuff. During the fermentation process the temperature is controlled by agitating the tobacco to lower the fermentation temperature to control bacterial growth without killing the bacteria. This action avoids high temperature levels which kills the bacteria. The fermentation process is allowed to proceed at a slow rate, typically over several months, to convert the tobacco to snuff, but preventing over fermentation which would degrade the tobacco into a compost type of product.
The fermented snuff product is typically cut into the desired particle sizes, and additives such as salt and ash are traditionally used as preservatives to retard mold, or to control pH or further fermentation. Flavorants such as wintergreen, attar of rose, or other ingredients are added to give the product a distinctive flavor, and the moisture level is adjusted to that the final product has a moisture content of from 45 to 60%.
In the present invention a stabilization process is utilized after the fermentation step to reduce the level of bacteria in the fermented snuff product, and to retard microflora recovery and oxidation to promote longer shelf stability of the snuff product.